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General Hazard Type
Return Home, to RSAP-V3 Wiki General Hazard Type The General Hazard Type categorizes Roadside Hazards into broadly similar types of objects. The General Hazard Types available in RSAP are: Point Hazards' ' are any object on the roadside or in the median that can be represented as a single point in space. Generally speaking, a point hazard would be any object whose actual length and width are less than about three feet (i.e., about half the width of a passenger vehicle). · Pole, Tree, or Sign · TerminalEnds · Crash Cushions_Gating · Crash Cushions_NonGating Line Hazards are any object on the roadside or in the median that can be represented as a line in plan-view. Line hazards include longitudinal barriers, clear zone edges (i.e., tree line, fence, etc.), edge of median, and other objects which can be represented by a line. There are two types of line hazards: Longitudinal Barriers ''include guardrails, concrete barrier, cable, barrier, various median barriers, etc.' '''The start and end stations and Offsets of longitudinal barriers must be specified. The Offset is measured from the Baseline to the center line of the barrier. A width of the barrier is also specified. A longitudinal barrier may or may not be parallel with the road. In the event the barrier has a flare, the start station and Offset and the end station and Offset should be entered to represent the flare. Barrier sections parallel to the road should be entered with the starting Offset and the ending Offset as equal. In Figure 26 there is a small flare in the length-of-need section of the terminal. This should be entered with the appropriate starting and ending Offset . The w-beam, however, continues parallel to the road. The remaining w-beam, therefore, should be entered with the starting and ending Offsets being equal. It is important to enter coincident points with the same station and Offset. If a gap is left in the longitudinal barrier data entry, this gap will be modeled without the barrier. For example, the end of a flared section of guardrail should have an identical end-station and end-Offset as the beginning of the parallel section of guardrail. The width of the barrier should be entered in the value field. · BridgeRails · Guardrails_Flexible · Guardrails_Rigid · Guardrails_SemiRigid · MedianBarriers_Flexible · MedianBarriers_Rigid · MedianBarriers_SemiRigid Spedial Edges One line hazard category which may not be self-explanatory is the special edge category. The special edge category is a line hazard category, therefore is defined using beginning station and Offsets and ending station and Offsets. Special edges include some imaginary lines and some real lines which have been added to account for Roadside Hazards which are present, but may or may not be engineered. For example, special edges include an edge of the median, an edge of the water, a clear zone edge, etc. Crossing any one of these lines obviously has consequences which should be considered. Additionally, the adding these features will allow the total crashes (i.e., trajectory path intersections) with the feature to be counted and reported in the analysis. · Median Edge -- New to this version of RSAPv3 is the ability to model median cross-over crashes. Errant vehicles can only cross this line hazard if it is specially defined, RSAPv3 does not automatically define the median edge when a median is indicated in the highway characteristics. To define this hazard for Divided Highways on the same alignment (i.e., Baseline in the middle), specify the start and end station and Offset of the left and right median edges. If the median width varies along the project, the beginning and ending Offset can be set appropriately. More dramatic changes should be modeled using multiple median edge segments. In the event the highway is on independent alignments and modeled as two, one-way roads, the median edge can also be added to these analyses. · Water -- Water hazards include streams, lakes, and other bodies of water which an errant vehicle's path may intersect. For example, an errant vehicle may penetrate a longitudinal barrier such as a bridge rail and the vehicle path may lead to a water hazard next (i.e., these lines may be coincident in plan view, but have different elevations.). The errant vehicle may penetrate guardrail, traverse a slope, then intersect the water hazard. The water hazard is defined by a series of lines with stations and Offsets. For example, when a stream crosses under a bridge, three water Line Hazards should be defined on each side of the bridge (i.e., the line parallel to the bridge rail and the two lines perpendicular to the bridge). · ClearZoneFence · GenericRigidWall · Rock Ledge · TreeLine